<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Loading</title>
    <style>
        *{
            margin:0;
            padding:0;
            box-sizing: border-box;
        }
        body{
            display:flex;
            justify-content:center;
            align-items: center;
            height: 100vh;
        }
    </style>
</head>
<body>
    <h1>加载中...</h1>
</body>
</html>